Radio tuning apparatus



y 9, 9 7E. A. GSCHWIND 2,250,761

RADIO TUNING A PPARATU Filed Oct. 7, 1940 2 Sheets-Sheet i INVENTOR.

y 1941. E. A. GSCHWIND I 2,250,761

I RADIO TUNING APPARATUS Filed Oct. 7, 1940 2 Sheets-Sheet 2 INVENTOR.

Edmund a6cfzwmczi Patented July 29, 1941 RADIO TUNING APPARATUS Edmund A. Gschwind, Chicago, Ill., assignor to Stewart-Warner Corporation, Chicago, 111., a corporation of Virginia Application October 7, 1940, Serial No. 360,021

Claims.

This invention relates to new and improved push button tuning mechanism, and more par- I ticularly to tuning mechanism of this character especially adapted for use with radio receiving sets.

The present commercial type of radio broadcast receiver comprises a tuning element, such as a variable condenser, which requires very accurate adjustment to tune'in a desired station properly and with good tone quality. A push button tuner for such sets must therefore be capable of rotating or otherwise moving the associated tuning element with a great degree of accuracy and with uniformity of movement in repeated use. Cost limitations in commercial practice require a tuner to be produced in quantities at a minimum of expense. This requires in turn that the parts of the tuner be capable of production without working to extremely close tolerances. It also requires that the assembly and adjustment of the parts be simple and that parts be interchangeable.

It is an object of the present invention to provide a new and improved push button tuner which is simple in design and operation and adapted for commercial production.

It is a further object to provide a construction in which the push rod-s or push button slides are Other further objects will appear as the description proceeds.

I have shown certain preferred embodiments of my invention in the accompanying drawings, in which- Figure 1 is a plan view of the tuning apparatus and the associated tuning element;

Figure 2 is a view of the construction" of Figure 1 taken on-line 22 of Figure 1'; and

Figure 3 is a fragmentary vertical section illustrating the construction.

In the drawings, the frame ll supports the tunthrough similar slots in the ing element l2, which is shown in this case as a two gangcondenser. The frame II also supports thecam shaft l3 which supports a plurality of sector-shaped cams [4, as shown in Figure 3. A manual drive disc I5 is supported on stub shaft IS in a bracket [1 secured to "the front of the frame II. This disc [5 drives a gear l8 which in turn drives gear l9 carried on stub shaft 20 supported by frame 11. Shaft 20 further carries gear 2| which drives gear 22 carried on stub shaft 23 extending from frame I L This shaft 23 carries the small gear 24 meshing with gear 25, which is secured to the shaft 26. This shaft 26 isin alignment with the cam shaft 13' and is connected therewith by means of the magnetic clutch 21..

The opposite endof shaft-.13 carriesa gear section 28 which meshes with the gear 29 secured to. the shaft 30 of the condenser I2. This shaft 30- also carries the cable drum 3| which drives the dial cable 32. This cable 32' passes around idler pulleys 33,. 3'4 and 35' and serves to move thepointer 36 above the dial strip 31. The cam shaftl3 carries the clamping mechanism 38, by meansof which the cam sectors [4 may be clamped to rotate with the shaft I 3' or may be released for adjustment. This clamping mechanism is conventional and need not be further described since it forms no part of the present invention.

The frame II also carries the upper lever paot shaft 39 upon which are pivoted a plurality oflevers 40. These levers are each formed of two spaced members joined at an intermediate point by the drive member 4! and at their ends by the cam contact member 42'. The lower lever pivot shaft 43 is carried by the frame I I below the cam shaft l3 and carries .a plurality of levers 44; These levers 4 are also formed of two spaced members, these members being joined by cam drive member 45'. The lowerYlevers 44 are provided with an arcuate surface 46 to be engaged by the drive members 41 carried by the upper levers 40. It is to be noted that the drive member 4| is provided with a reduced portion 41' so that it only engages one side ofthe lower cam lever 44. This prevents any variable movement of the parts due to imperfectalig'nm'ent of members, as might oc-v cur if both sides of the lever M were engaged by the cylindrical member 41 This, therefore, aids in making'the construction accurate in operation without the necessity for extremely close manufacturing tolerances. p

The frame H is provided with an intermediate cross piece 48' having a plurality of slots toreceive the pushbutton slides 49; These slides passfront cross frame member 50 and are provided with springs 5| engaging the member 50 and having their opposite ends extending through openings in the slide so as to maintain the slide normally at its outer limit of movement. The slide 49 is shown as provided with the push button 52, but it may be operated by any desired means.

The frame I carries the insulating switch base 53, as best shown in Figure 2, which base supports the spaced switch contacts 54 and 55. The contact 55 has an extended upper portion carrying a disc 56 formed of insulation. The switch is connected in circuit with the magnetic clutch 21. This magnetic clutch is normally in connecting or clutching position. When' current is through it, it is declutched. Consequently when switch contacts 54 and 55 are in engagement the clutch is out of operation. The switch operating shaft 5'! has a crank portion 58 extending under the slides 49 and normally fitting in notches 59 in these slides. The end of the shaft 51 is provided with an upwardly extending portion 60, adapted to engage the insulating disc 55 to close the switch when the shaft is rotated in clockwise direction, as seen in Figures 2 and 3. It will be seen that movement of any push button slide 49 inwardly will serve to move the notch 59 of the slide away from the portion 58 of the shaft 5?, and that the shaft 51 will be rocked in a clockwise direction to close the switch. 'The inner end of each slide 49 is provided with an elongated foot portion 6| adapted to engage the operating member 4| of the adjacent upper pivot lever 45.

The upper levers 40 are held at their limit of clockwise movement by springs 63 which have one end secured to a lever 40 and the opposite end secured to the frame member 64. The move- -ment of the levers in this direction is limited by the contact of-the intermediate drive member 4| with the foot portion 6| of the associated slide 49. The lower levers 44 are held at their counterclockwise limit of movement by similar springs 55, the opposite ends of which are secured to the rear portion of the frame I l. The movement of these levers in this direction is limited by the contact of the arcuate surface 46 with the drive member 4| of the associated upper lever 40.

In the operation of the device, in order to' set up the cam actuated by any given push buttlon for a desired station, the clamping of the cam is released by means of mechanism 38. The push button 52 associatedwith the cam being set up is then thrust inwardly to its limit of movement which, by pressure against the drive member 4| of the upper lever 40 transmitted through the drive member 4| to the lower lever 44, forces the two levers inwardly about their pivots so that the cam contact members 42 and 45, respectively, engage the opposite faces of the associated cam I4. If the cam I4 is in an intermediate position, one or the other of the ment-of any cam maybe readily changed inthe' manner described whenever desired 'j;

passed During the operation of the tuning assembly for tuning the radio set after the cams are properly set up, any station for which a push button is adjusted may be instantly tuned in by pushing the designated button inwardly to its limit of movement. The initial operation of this movement serves to rock the shaft 51 and by closing switch 53 disconnects the manual tuning mechanism by declutching the magnetic clutch 21. Consequently the shaft |3 rotates easily upon pressure against the cam M by the associated lever drive members 42 and 45. It will be noted that the indicating dial mechanism is cmnected to the tuning element l2 so that the dial will be moved by push button tuning and show the relative position of the tuner. The tuning assembly is always instantly adjusted for manual tuning, which is accomplished by means of the manual drive disc l5 and its associated gear train connecting it to the shaft l3 through the magnetic clutch 21.

While I have shown certain preferred embodiments of my invention, these are to be understood to be illustrative only, as it is capable of variation to meet differing conditions and requirements. I contemplate, therefore, such changes and modifications as come within the spirit and scope of the appended claims.

What is claimed is:

1. Radio tuning apparatus comprising a tuning element, a cam shaft having a driving connection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surfaces, a pair of levers pivotally supported adjacent the cam, each lever having means adapted to coact with one of the pair of cam surfaces, and means for swinging the levers about their pivots to cause coaction of said means with the cam to rotate the cam shaft.

2. Radio tuning apparatus comprising a tuning element, a cam shaft having a driving connection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surfaces, a pair of levers pivotally supported upon opposite sides of the cam, each lever having means adapted to coact with one of the pair of cam surfaces, and means for swinging the levers about their pivots to cause coaction of said means with the cam to rotate the cam shaft.

3. Radio tuning apparatus comprising a tunmeans adapted to coact with one of the pair of cam surfaces, the levers having interengaging portions whereby movement of one lever toward the cam causes simultaneous movement of the other lever in the same direction, and means for moving said levers to cause coaction of the lever means and cam to rotate the cam shaft.

4. Radio tuning apparatus comprising a tuning element, a cam shaft having a driving connection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surfaces, a pair of levers pivotally supported adjacent the cam, each lever having means adapted to coact with one of the pair of cam surfaces, the levers overlapping each other with'the outer leverhaving means engaging the inner lever, means forswinfging the outer lever toward the cam and thereby-swinging the inner lever in the same direction andcausing 'the' cam engaging means on the levers to engage the cam to rotate the shaft.

5. Radio tuning apparatus comprising a tuning element, a cam shaft having a driving con nection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surfaces, a pair of levers pivotally supported upon opposite sides of the cam shaft, each lever having means adapted to coact with one of the pair of cam surfaces, the levers overlapping to engage cam surfaces on the opposite side of the cam shaft to the lever pivot, and means for simultaneously moving the levers about their pivots to cause coaction of the lever means with the cam surfaces to rotate the cam shaft.

6. Radio tuning apparatus comprising a tuning element, a cam shaft having a, driving connection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surfaces, a pair of levers pivotally supported upon opposite sides of the cam shaft, each lever having means adapted to coact with one of the pair of cam surfaces, the levers overlapping to engage cam surfaces on the opposite side of the cam shaft to the lever pivot, means onthe outer lever to engage and move the inner lever, and means for moving the outer lever whereby the lever means of the two levers are caused to coact with the respective cam surfaces to rotate the cam shaft.

'7. Radio tuning apparatus comprising a tuning element, a cam shaft having a driving connection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surfaces, a pair of levers pivotally supported adjacent the cam, each lever having means adapted to coact with one of the pair of cam surfaces, and an independently mounted sliding member adapted to swing the levers about their pivots to cause coaction of the lever means with the cam to rotate the cam shaft.

8. Radio tuning apparatus comprising a tuning element, a cam shaft having a driving connection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surfaces, a pair of levers pivotally supported adjacent the cam, each lever having means adapted to coact with one of the pair of cam surfaces, the levers having intere-ngaging portions whereby movement of one lever toward the cam causes simultaneous movement of the other lever in the same direction, and an independemtly mounted sliding member for engaging the first lever to swing both levers to cause coaction of the lever mean-s and cam to rotate the cam shaft.

9. Radio tuning apparatus comprising a tuning element, a cam shaft having a driving connection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surf-aces, a pair of levers pivotally supported upo-n opposite sides of the cam shaft, each lever having means adapted to coact with one of the pair of cam surfaces, the levers overlapping to engage cam surfaces on the opposite side of the cam shaft to the lever pivot, and an independently mounted sliding member for simultaneously swinging the levers about their pivots to cause coaction of the lever means with the cam surfaces to rotate the shaft.

10. Radio tuning apparatus comprising a tuning element, a cam shaft having a driving connection with the tuning element, a cam adjustably carried by the cam shaft, said cam having a pair of cam surfaces, a pair of levers pivotally supported upon opposite sides of the cam shaft, each lever having means adapted to coact with one of the pair of cam surfaces, the levers overlapping to engage cam surfaces on the opposite side of the cam shaft to the lever pivot, means on the outer lever to engage and move the inner lever, and a sliding member having a foot engaging the outer lever whereby an inward movement of the sliding member swings both levers simultaneously to cause the lever means of the two levers to coact with the respective cam surfaces to rotate the cam shaft.

EDMUND A. iGSCHWIN D. 

